1. Field of the Invention
The invention relates generally to mine haulage vehicles and more particularly to a shuttlecar having a plurality of sections connected by articulation joints.
In underground mining, the loose mined material must be transported from the mine face to a haulage system for removal from the mine. It is often not possible to transport the loose mined material on a fixed conveyor. For example, the path which must be travelled by the material may be too long or tortuous, or it may intersect with major underground tunnels so that a fixed conveyor would create an unacceptable obstruction. In these and other circumstances, a vehicle is used to transport the loose mined material away from the mine face. Such a vehicle must be dimensioned to operate within the confines of the mine. It must be sufficiently low to permit it to operate on undulating terrain in low tunnels, and it must be able to negotiate short-radius turns between tunnels.
2. Description of the Prior Art
A number of vehicles have been designed to operate in mines. These vehicles include front end loaders, scoops, ram cars and shuttlecars. The scoops and ram cars have tractor sections including or connected to load-carrying cargo compartments. Such devices are manufactured by Envirotech Corp., and marketed under the EIMCO name.
In order to negotiate short-radius turns, some scoop-type vehicles are horizontally articulated about a vertical axis. This allows the vehicle to turn more easily at corners and to turn around after the loose mined material has been discharged. Turning a vehicle requires a relatively large area which limits the application of the prior art scoop-type vehicles.
Prior art shuttlecars have been designed to load and unload loose mined material without turning around. This is accomplished by using a central conveyor extending along the length of the shuttlecar to load and unload the material. Since the conveyor extends throughout the length of the shuttlecar, the load-carrying capacity of such a vehicle is relatively high.
However, the capacity of prior art shuttlecars with a conveyor is limited by the length, height and width of the vehicle. The height and width of the vehicle are dictated by the height and width of the mine tunnels in which the shuttlecar must operate and are fixed parameters. The length of a shuttlecar is dictated by the necessity of negotiating short-radius turns and undulations within mine tunnels. The longer the car, the less able it is to negotiate sharp turns and the more likely it is to be upset by undulations in the floors of the mine tunnels. In order to negotiate undulating mine floors, shuttlecars may be vertically articulated about a horizontal axis. Such a shuttlecar is disclosed, for example, in Canadian Patent No. 666,032 assigned to Joy Manufacturing Co.
A horizontally articulated shuttlecar is disclosed in U.S. Pat. No. 4,160,619. The vehicle disclosed in that patent has two body sections, each of which is necessarily shorter than a single-section shuttlecar and, thus, the carrying capacity of the vehicle is not substantially greater than a single-section shuttlecar. Furthermore, the majority of the load is carried in a compartment located at one end of the vehicle which equates the vehicle to a scoop-type vehicle with a discharge conveyor. The bulk of the vehicle remains lightly loaded, unlike a true shuttlecar wherein the load carrying compartment extends throughout the length of the vehicle. The vehicle disclosed in the patent is also deficient in that the horizontal articulation joint is not strong enough to withstand the normal wear which occurs in a mine.